Wireless receiving circuit



V and wherein a uniform change in t Patented July i, i924.

ntran smrss MTEN cerros MM G. BAISEJ, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESIINGHOUSE MECTRI C& MANUFACTURII\TG COMPANY, A CORPORATION OF PENI TSYLVANIA.

WIRELESS. BECEWING- GIRCUII.

Application filed December 11, 1922. Serial No. 606,029.

'T0 all whom t may 00nern:

Be it known that I,MAX C. BATSEL, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Wireless Receiv ing Circuits, of which the following is a specification.

My invention relatcs to wireless receiving sy teme and, more especill ,rto the coupling of}ie enerative vacuum-tu e circuits..

' n 1ts broad a ect, an object of my invention is to provi e an arrangement of feedback circuits embodying a vacuum-tube device which admits of variations in the tuning of one circuit without substantially changing the tendency for said tube to function as an oscillation generator. More specifically, an object of'my invention is to provide a regenerative system wherein the regenerative action of the system. is independent of the thereof e degree of feed-back coupling may be obtained w1thout afl'ectin the tuning of said system. Another 5bject of my invention is to provide means Whereby a plurality of variometers may be employed for adjusting the tuning and the feed-back relation of a regenerative circuit in accordance with the abovementioned desired results.

In regeneratiire continuous-wave systems prior to my present invention, the tuning of the system has necessitated simultaneons adjustments in the tickler or feed-back portiens of the system to obtain optimum oper'ating conditions.

I have found, however, that, by providing a construction comprisin a continuously var1able tuning reactor an a contmuous vanable feed-back reactor, whichare disposed in a mutually inductive relation, and an auxil' H 1ary reactor, which 1s connected msenes-c1r-' cuit'relation with one of said first-mentioned reactors, andtightl coupled to the other, the above-mentioned desired results may be readil obtained.

Wit these and other objects in view, my inventin further consists in the details of construction and operation and circuit arrangement hereinafter described and claimed and illustrated in the ac0ompanyingdrawing wherein,

igure 1 is a diagrammatic and sideelevational view of circuits and apparatus embodying my invention, and

Fig. 2 is a detail side elevational view of a modificatin.

ln the embodiment of my invention shown m Fig. '1 of the drawing, a tubular member 1 1sprovrded, at one end, with a winding 2 having spaced portions 3 and 4 constitutmg the stationary element of a variometer 5. r

A movable element 6 of the variometer 5 coniprises a cylindrical form 7 carrying a .at the.free end of the stationary winding 2.

Indutively coupled to the variometer 2 is a second-variometer 13 comprising a windin 14 which encircles the other end of said tubular member 1 and which constitutes the stationary windin of the variometer 13. The V stat1onary wmding 14 may comprise spaced portions 15 and 16. A movabl element for the variometer 13 may comprise a form 17 carrying a windin 18 and is mounted for rotation within the stationary coil 14 by means of a pvot rod 19 extendin'g therefrom through the tubular member 1.

As in the case of the variometer 5, the two windings thereof may be connected in seriescircuit relation by means of the rod 19, a spring member 21 secured thereto and a conductor 22 which extends to a free terminal of the portion 15 of the winding 14.

Apair of auxiliary windings 23 and 24 are disposed upon bpposite sides of the portions 15 and 16 of the stationary winding 14 of the variometer 13 and.immediately adjacent thereto. Thewindings 23 and 24 are connected in series-circuit relation with the .stationary winding of the variometer 2 by means of a conductor 25. The windings 23 v and 24 are designed to providea certain additional degree of coupling between the variometers 5 and 13 over and above that normally existing therebetween by reason of their side-by-side relation, all as hereinafter ex lained.

e free terminal of the rotor winding 8 of the variometer 2 may be connected to an antenna 26 through a condenser 27 wh1le the free terminal of the auxiliary wmdmg 24 may be connected to ground through a conductor 28, to provide a grounded antenna circuit.

A three-electrode tube 29 of customary de-- sign has its input electrodes 31 and 32 co n nected to a point in the antenna circuit 1ntermediate the antenna condenser 27 and the variometer 5 and to ground by means of conductors 33 and 34-, respectively,thereby providing a grid circuit includingthe variometer 5 and the auxiliary stationary coils 23 and 24, The output electrodos 32 and 35 of the tube are connected, by conductors 36 and 37, to the terminals of the variometer 13. The plate circuit, which includes the variometer 13, includes also a source 38 of direct-current energy and a telephone translating device 39.

' The equation between the amplifying factor u of a vacuum-tube device and the several constante of an oscillatory circuit necessary for oscillations to start or to be maintained is where, as applied to Figi 1, M is the mutual inductance between the plate and grid circuits by reason of the variometers 5 and 13 and the auxiliary windings 23 and 24; L is the combined self inductance of the tuning variometer 5 and the auxiliary windings 23 and 24; C is the combined eective capacity of the condenser 27 and the antenna 26 to ground; r is the resistance of the variometer 5 and the auxiliary windings 23 and 24; and R, is the internal resistance of the vacuum tube 29.

From the above relation, it is seen that, in

order to cause the tube 29 to have the same degree of regeneration, for various val-nes of the self-inductance L, the value of the mutual inductance M must vary in proper proportion with changes in L. By degree of regeneration is meant the extent to which the losses in the circuits are neutralized by the amplifying action of the tube 29. As hereinbefore stated, this desired result is obtained by providing the additional windings 23 and 24, which are serially included in circuit with the tuning variometer 5 and which are tightly coupled to the windings of the so-called feed-back variometer 13, the number of turns of said auxiliary windings being determined by the constants of the circuits and by the geometric arran ament of the various inductors. Hence, t e tendency for the tube 29 to oscillate, or the degree of regeneration, when the rotor 17 of the feed-back variometer 13 is in any fixed position, is independent of the varia-j tions m the position of the rotor 6 of the '17 are each 1?; inches long and 2% inches in diameter and are each wound with 38 turns of N o. 28 wire. The portions Band 4 of the stationary winding 2 each comprise 16 turns of No. 28 wire separated g inch. The portions 15 and 16 of the stationary winding 14 comprise two.groups of 16 turns of No. 28 wire spaced g inch apart. The portions 4 and 15 of the stationary windings are spaced linches apart. The 'auxiliary windings 23 and 24 each comprise 6 turns and are spaced inch from the .Windings 15 and 16, respectively. The capacity of the condenser 27 may very from approximately to 350 micro microfarads.

In the practical.operation of my invention, the rotor 17 of the feed-back variometer 13 is adjusted to the point where maximum intensit of received signals obtains, as indicated y the telephonereceivers 39. The rotor 7 of the timing variometer 5 is then adjusted to bring the system into a condition of resonance with the received signal impulses, the degree of regeneration determined b the position of the rotor 17 remaining su stantially constant, all as ex plained more fully hereinbefore.

The detail construction shown in Fig. 2 is diierentiatedover that shown in Fig. 1 in the position of the auxiliary windings 23' and 24 in the space intermediate the portions 15 and 16' of the feed-back variometer 13'. The advantage of such arrangement is in the provision of a closer coupling between the several windings than is possible in the construction shown in Fig. 1.

While I have shown only two embdimente of my invention, for the pu ose of describing the same and illustrat1ng itsprinciples of operation, it is apparent that var10us changes and modificatrons may be made therein without departing from the spirit of my invention. I desire, therefore, t at only such lim1tations shall be imposed thereon as are indicated by the prior art or are specifically set forth in the appended claims.

I claim as my invention:

1. Apparatus comprising a pair of variable inductors disposed in mutual,inductive relation and an auxiliary inductor. disposed in mutual inductiverelation to said. pair of variable inductors and included in circuit z,eee,asi 8 with one of said variable inductors, whereby the mutual inductance of said inductors is a function of the self inductance of said last-mentioned variable inductor.

2. A thermionic relay having ingut and output circuits, variable inductors in iyidual to the res ective circuits' and disposed in mutual in uctive relation to admit of freeback coupling, and means for producing additional feeqoack couplin whereby the degree of regeneration is su%stantiall indegendent of the tuning of the varia le inuctor in said input circuit.

- 3. An evacuated electric device having input and output circuits, variable inductors individual to the respective circuits providing feed-back coupl1ng therebetween and means for establishin such additional feedback coupling that t e degree of regeneration is substantially independent of all adjustments of the inductor in said input'circuit.

4. A receiving system comprising, in combinatin, a space-discharge device of the three-electrode type having plate and grid circuits, an adjustable tuning inductor included in said rid circuit, an adjustable inductor include in said plate circuit and inductivel coupled to said tuning inductor and an a ditional inductor included in circuit with said tuning inductor and disposed in such inutual inductive relation to said adjustable inductors that the tendenc for said device to oscillate is substantial y independent of variations in said tuning inductor.

5. A space-discharge device of the threeelectrode type having plate and grid circuits, a variable tuning inductor included in said id circuit, a variable inductor 'include in said late circuit and inductively coupled to sai tuning inductor to rovide an adjustable feed-back coupling etween said c1rcuits and an inductor serially in eluded in circuit with said tuning inductor and disposed in such inductive relation to said varible inductors that, for any predetermind degree of regeneration, the tend' ency for said device to oscillate or to be mamtained in an oscillatory state is substantially unaflected by variations in the value of said tuning inductor.

6. A space-current device having input and output circuits, a variable tuning inductor included in said input circuit, a variable inductor included in said output circuit and inductively cou led to said tuning inductor to provide an adjustable feed-back -coupling between said circuits, each of said inductors comprising a pair of relatively movable series-connected coils, and an inductor included in circuit with said tuning inductor and disposed in such inductive relation to said variable inductors that the degree of regeneraton is substantially indea relative y movable coil serially included in said input circuit, a second variable in-;

ductor also having a relatively stationary coil and a, relatively movable coil serially included in said output circuit, said stationary coils being mouhted in inductive relation to provide feed-back coupling between said circuits, and aninductor included in circuit with said tuning inductor and disposed in relatively close inductive relation to said second variable inductor.

8. A thermionic device having input and outut circuits, a variable tuning mductor having a relatively .stationary coil and a relatively novable coil serially included in said input circuit, a Second Variable inductor also having a relatively stationary coil and a relatively movable coil serially included in said output circuit, said stationary coils being mounted in inductive relation to provide feed-back coupling between said cir cuits and a coil connected in circuit.with

said tuning inductor and having.suchdeuctors, that, for any predetennined degree of feed-back coupling, the tendency for said device to oscillate is substantially ndepend- :nt of the variatins of said tuning inducor. v

9. In a wireless receiving system,a spacedischarge device of the three-electrodo type having plate and grid circuits,variable inductors individual to each circuit and arranged in inductive relation, each inductor comprising two relatively movable coils in series, an additional inductor connected in series circuit relation with said 'd inductor and disposed in such inductive relation with respect to said inductors that the tend= ency for said device to function as an oscillator remains substantially constant for variations in the value of said grid-circuit inductor, and a work circuit connected in shunt relation to said series connected inductors.

10. Apparatus comprising a pair of variometers, each variometer comprising rela-.

tively stationary and movable coils, means for supporting said statidnary coils m spaced relation, means for rotatabl mount.

ingsaid movable coils within sai station- -ary coils, an additional stationary winding disposed immediately adjacent to one sai stationary coils and series connected with the others, a space-current device of the three-electrode type having plate and grid circuits, said grid circmt includin said additional winding and coils connected in circuittherewith, said late circuit includmg the remaming pair of station ry 'and mvable coils, said additional coil being so coupled to said remainin pair of co1ls that, for any predetermine position of the variable plate-circuitcoil, the degree of regeneration 1s substantially constant for all 1nositions of the grid circuit coils.

1 As an article.of manufactura, a member carrying spaced windings, relatively acting, respectively, With said spaced Windings, and an additional winding ponnected in series-circuit relation with one of said spaced windings, said additional winding comprising spaced portions substantially equally inductively coupled to another of said spaeedwindings.

18. As an art1cle of manufactura, a member carrying spaced windings, relatively movable members carrying windings for co- 'acting, respectively with said spaced windings, and an addit1onal winding connected m ser1es-c1rcu1t. relation w1tlr one of said spaced Windings, said additional windin,r

comprising spaced portions carried by sai member and di'sposed upon opposite sides of another of said spaced winding.fs to provide a tight coupling therewith.

14. As an article of manufacture, a msm;

ber carrying spaced windings, relatively r movable members carrying windngs for coacting, respectively, with said spaced windings, means for causing one of said 'c0 operating stationary and movable windings to function as a tuning variometer, means for causing another pair of co-operating windings to function as a feed-back variometer andan additional winding connected in series-circuit relation to said tuning variometr and com rising spaced portions tightly coupled to t e stationary windings of -said feed-back variometer.

In testimonywhereof, I have hereunto subscribed my name this 8th day of December 1922.

MAX o. BAT SEL. 

